U.S. patent application number 17/288309 was filed with the patent office on 2021-12-02 for process for the preparation of 3,3,4-trimethylcyclohexylidene bisphenol (bp-tmc).
The applicant listed for this patent is Covestro Intellectual Property GmbH & Co. KG. Invention is credited to Anja Ehrig, Lars Frye, Kristof Heylen, Johan Vanden Eynde.
Application Number | 20210371365 17/288309 |
Document ID | / |
Family ID | 1000005796861 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210371365 |
Kind Code |
A1 |
Vanden Eynde; Johan ; et
al. |
December 2, 2021 |
PROCESS FOR THE PREPARATION OF 3,3,4-TRIMETHYLCYCLOHEXYLIDENE
BISPHENOL (BP-TMC)
Abstract
The present inventions relates to the preparation of
3,3,5-trimethylcyclohexylidene bisphenol. Especially, the present
invention relates to the preparation of
3,3,5-trimethylcyclohexylidene bisphenol from
3,3,5-trimethylcyclohexanone and phenol in the presence of a
gaseous acidic catalyst. The preparation comprises a first drying
step and a second drying step wherein in the second drying step the
temperature is increased in comparison to first drying step or in
the second drying step the pressure is lowered in comparison to
first drying step, or in second drying step both the temperature is
increased and the pressure is lowered in comparison to the first
drying step (d1).
Inventors: |
Vanden Eynde; Johan;
(Zwijnaarde, BE) ; Heylen; Kristof; (Zemst,
BE) ; Ehrig; Anja; (Leverkusen, DE) ; Frye;
Lars; (Leichlingen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Covestro Intellectual Property GmbH & Co. KG |
Leverkusen |
|
DE |
|
|
Family ID: |
1000005796861 |
Appl. No.: |
17/288309 |
Filed: |
November 13, 2019 |
PCT Filed: |
November 13, 2019 |
PCT NO: |
PCT/EP2019/081106 |
371 Date: |
April 23, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 37/82 20130101;
C07C 37/84 20130101; C07C 37/20 20130101; C07C 37/685 20130101 |
International
Class: |
C07C 37/20 20060101
C07C037/20; C07C 37/68 20060101 C07C037/68; C07C 37/84 20060101
C07C037/84; C07C 37/82 20060101 C07C037/82 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2018 |
EP |
18208309.7 |
Dec 6, 2018 |
LU |
LU101025 |
Claims
1. A process for preparing 3,3,5-trimethylcyclohexylidene bisphenol
comprising less than 1000 ppm of phenol, the process comprising the
steps of: (a) reacting 3,3,5-trimethylcyclohexanone and phenol in
the presence of an acidic catalyst to give a product mixture
comprising 3,3,5-trimethylcyclohexylidene-bisphenol in the form of
an 3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct and
water, (b) separating the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct from the
product mixture, wherein the process further comprises the steps
of: (d) removing the phenol from the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct by (d1)
drying the 3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct
at a temperature of less than or equal to 160.degree. C. and an
absolute pressure of from 200 mbar to 20 mbar until an intermediate
product mixture comprising
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct and
3,3,5-trimethylcyclohexylidene-bisphenol is obtained, this
intermediate product mixture having a phenol concentration below 10
wt.-%, and (d2) drying the intermediate product mixture obtained
from step (d1) at a temperature from 150.degree. C. to 180.degree.
C. and an absolute pressure of less than 50 mbar wherein in step
(d2) the temperature is increased in comparison to step (d1) or in
step (d2) the pressure is lowered in comparison to step (d1), or in
in step (d2) both the temperature is increased and the pressure is
lowered in comparison to step (d1).
2. The process of claim 1, wherein in step (d2) the temperature is
at least 20.degree. C. higher than in step (d1).
3. The process of claim 1, wherein in step (d2) the pressure is at
least 10 mbar lower than in step (d1).
4. The process of claim 1, wherein in step (b) the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct is obtained
as crystals comprising 3,3,5-trimethylcyclohexylidene bisphenol and
phenol.
5. The process of claim 1, wherein at least one of steps (d1) or
(d2) is conducted in a rotary dryer.
6. The process of claim 1, wherein the phenol is removed from the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct crystals in
absence of any organic solvent except phenol.
7. The process of claim 1, wherein neither the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct nor the
3,3,5-trimethylcyclohexylidene bisphenol are molten during steps
(d1) or (d2).
8. The process of claim 1, wherein the
3,3,5-trimethylcyclohexylidene bisphenol obtained in step (d2) has
a phenol content of less than 1000 ppm, preferably less 300 ppm,
more preferably less than 200 ppm, most preferably less than 150
ppm.
9. The process of claim 1, wherein steps (d1) and (d2) are
performed continuously.
10. The process of claim 1, wherein in step (d1) the phenol
concentration of the crystals is reduced to below 5 wt.-%.
11. The process of claim 1, wherein in step (b) the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct is separated
by (b1) removing the catalyst and the water by distillation, (b2)
crystallizing the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct from the
distillation residue, and (b3) separating the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct by
filtration.
12. The process of claim 1, wherein the process further comprising
the step of (c) recrystallizing the
3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct crystals
obtained in step (b) from liquid phenol.
13. The process of claim 1, wherein an amount of 20 to 60 wt.-% of
the 3,3,5-trimethylcyclohexylidene bisphenol obtained in step (d2)
is conducted back to step (d1).
14. The process of claim 1, wherein in step (d1) the temperature is
higher than or equal to 135.degree. C. and less than or equal to
160.degree. C.
15. A process according to claim 1, wherein in step (d1) the drying
the 3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct is at a
temperature less than or equal to 145.degree. C.
16. A process according to claim 1, wherein in step (d1) the drying
the 3,3,5-trimethylcyclohexylidene-bisphenol-phenol-adduct is at a
pressure in a range of 50 to 25 mbar.
17. A process according to claim 1, wherein in step (d2) the drying
the intermediate product mixture obtained from step (d1) is at a
pressure of less than 20 mbar.
18. A process according to claim 1, wherein the
3,3,5-trimethylcyclohexylidene bisphenol obtained in step (d2) has
a phenol content of less than 150 ppm.
19. A process according to claim 1, wherein an amount of 30 to 50
wt % of the 3,3,5-trimethylcyclohexylidene bisphenol obtained in
step (d2) is conducted back to step (d1).
20. A process according to claim 1, wherein in step (d1) the
temperature is greater than or equal to 135.degree. C. and less
than or equal to 145.degree. C.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. national stage application, filed
under 35 U.S.C. .sctn. 371, of International Application No.
PCT/EP2019/081106, which was filed on Nov. 13, 2019, and which
claims priority to Luxembourg Patent Application No. LU101025,
which was filed on Dec. 6, 2018 and European Patent Application No.
18208309.7, which was filed on Nov. 26, 2018. The contents of each
are hereby incorporated by reference into this specification.
FIELD
[0002] The present inventions relates to the preparation of
3,3,5-trimethylcyclohexylidene bisphenol. Especially, the present
invention relates to the preparation of
3,3,5-trimethylcyclohexylidene bisphenol from
3,3,5-trimethylcyclohexanone and phenol in the presence of a
gaseous acidic catalyst. The preparation comprises a first drying
step and a second drying step wherein in the second drying step the
temperature is increased in comparison to first drying step or in
the second drying step the pressure is lowered in comparison to
first drying step, or in second drying step both the temperature is
increased and the pressure is lowered in comparison to the first
drying step (d1).
BACKGROUND
[0003] The preparation of 3,3,5-trimethylcyclohexylidene bisphenol,
hereinafter also referred to as BP-TMC, from
3,3,5-trimethylcyclohexanone, hereinafter referred to as TMC-one,
as a first reactant and phenol as a second reactant in a reaction
vessel in the presence of a gaseous acidic catalyst is known per
se.
[0004] Basically the reaction proceeds as follows according to
Scheme 1:
##STR00001##
[0005] EP0995737A1 discloses the preparation of BP-TMC from TMC and
phenol in the presence of acidic catalyst already. EP0995737A1 also
mentions that the obtained reaction product is dried but does not
disclose any details thereto.
[0006] EP1277723A1 also discloses the preparation of BP-TMC from
TMC and phenol in the presence of acidic catalyst already, too.
Also EP1277723A1 mentions that the obtained reaction product is
dried. However, EP1277723A1 does not disclose any details to the
drying of the reaction product either.
[0007] According to EP1277723A1 BP-TMC can be obtained as crystals
of an BP-TMC-phenol-adduct intermittent. The content of EP1277723A1
is incorporated into the present description by reference.
[0008] In an industrial process for the production of BP-TMC these
crystals comprise from 60 to 70 wt.-% of BP-TMC and from 30 to 40
wt.-% of phenol; these crystals also may comprise inevitable
impurities in a very low amount, especially less than 1000 ppm.
These inevitable impurities are introduced by the reactants and
catalysts, e.g. One skilled in the art knows the types and amounts
of all major inevitable impurities. BP-TMC then is obtained as
crystals comprising at least 99 wt.-%, preferably at least 99.5
wt.-%, most preferably at least 99.9 wt.-% of BP-TMC and less than
or equal to 1000 ppm, preferably less than or equal to 300 ppm,
most preferably less than or equal to 200 ppm of phenol by drying.
The amount of BP-TMC plus the amount of phenol plus the amount of
inevitable impurities sums up to 100 wt.-% always. During drying
the phenol is evaporated.
[0009] However, the melting point of pure BP-TMC at atmospheric
pressure (1013.25 mbar) is 210.degree. C. and the thermal stability
of BP-TMC requires drying temperatures lower than 200.degree. C. to
avoid that the BP-TMC is degraded during drying. The degradation of
BP-TMC causes a final product with more impurities and of poor
crystal structure which is difficult to transport and to use in an
further process, e.g. the preparation of a polycarbonate using
BP-TMC and phosgene in a phase boundary process or using BP-TMC in
a melt transesterification using diphenyl carbonate.
[0010] Therefore it is not possible to keep a whole setting up
comprising crystals comprising BP-TMC obtained in an industrial
process for the production of BP-TMC in liquid state during drying.
The phenol content of the crystals is reduced during drying.
Technically it is desired to keep the whole setting up comprising
crystals comprising BP-TMC in liquid state during drying since this
would enhance the drying, especially it would accelerate the
drying. However, this is not possible for the reasons explained
above. Therefore it is required to conduct the drying of the
crystals comprising BP-TMC in a solid state in a dryer. During
drying in a conventional dryer, e.g. a rotary dryer, the problem
occurs that due to the high amount of phenol--coming from the
evaporation from the crystals of the BP-TMC-phenol-adduct--in the
inner volume of the dryer the input of thermal energy has to be
very high to keep the temperature high enough to achieve a
reasonable evaporation of the phenol from the crystals of the
BP-TMC-phenol-adduct. This in turn leads to the situation that the
temperature of inner walls of the dryer has to be so high that the
crystals comprising BP-TMC which are in contact with the inner
walls of the dryer become liquid. This leads again to morphology
changes of the crystals, i.e. poor crystal structure, or even to
degradation of BP-TMC.
[0011] Since 2,2-Bis(4-hydroxyphenyl)propan (bisphenol A, BPA) has
a lower melting point (about 155.degree. C.) at atmospheric
pressure (1013.25 mbar) there is not the problem of decomposition
when BPA is converted into the liquid state. Therefore the methods
for drying BPA cannot be used for drying BP-TMC.
[0012] To overcome the above explained problems according to the
state of the art batch dryers are used for the drying setting up
comprising crystals comprising BP-TMC. These batch dryers change
the temperature over time and can thus avoid this issue. Batch
dryers are however more expensive to operate since they do not work
continuously resulting in large buffer volumes and they ask for
additional manipulation steps.
[0013] Another solution according to the state of the art, e.g. EP
1318132 A1, is to use a solvent in a recrystallization step that is
not mixable with phenol and BP-TMC. This will remove the phenol
from the adduct and form BPTMC crystals in such a solvent. As these
BP-TMC crystals are no longer part of an adduct between BP-TMC and
phenol, the melting point of these crystals are much higher
resulting into no phase change of the crystals due to the
temperature increase required for removal of such a solvent. It
will however also result into traces of this solvent to be found in
the end product. These traces of the solvent are adverse since they
may e.g. disturb the preparation of a polycarbonate resulting from
BP-TMC and phosgene or resulting from BP-TMC and diphenyl
carbonate.
[0014] It is also possible to use a water washing step to remove
the phenol from the adduct and remove the water in a drying step.
However there will be a high amount of water consumption required
to be able to remove the required phenol and a substantial higher
energy consumption to evaporate the water.
[0015] So, currently it is not possible to conduct drying in a
continuous solid drying process to obtain BP-TMC crystals with low
content of phenol, especially with a phenol content of less than
1000 ppm, preferably of less than 300 ppm, most preferably of less
than 200 ppm.
SUMMARY
[0016] Therefore it is an object of the present invention to
overcome the disadvantages of the state of the art.
[0017] Especially it is an object of the invention to provide a
process for preparing BP-TMC with a purity of at least 99 wt.-%,
the process comprising continuously conducted drying steps.
[0018] Surprisingly the object was achieved by the subject matter
of claim 1. Preferred embodiments can be found in the dependent
claims.
[0019] Especially the object was achieved by:
[0020] A process for preparing BP-TMC comprising less than 1000 ppm
of phenol, the process comprising the steps of: [0021] (a) reacting
TMC-one and phenol in the presence of an acidic catalyst to give a
product mixture comprising BP-TMC in the form of an
BP-TMC-phenol-adduct and water, [0022] (b) separating the
BP-TMC-phenol-adduct from the product mixture, wherein the process
further comprises the steps of: [0023] (d) removing the phenol from
the BP-TMC-phenol-adduct by [0024] (d1) drying the
BP-TMC-phenol-adduct at a temperature of less than or equal to
160.degree. C., more preferably less than or equal to 145.degree.
C. and an absolute pressure of from 200 mbar to 20 mbar, preferably
from 50 to 25 mbar, until an intermediate product mixture
comprising BP-TMC-phenol-adduct and BP-TMC is obtained, this
intermediate product mixture having a phenol concentration below 10
wt.-%, and [0025] (d2) drying the intermediate product mixture
obtained from step (d1) at a temperature from 150.degree. C. to
180.degree. C. and an absolute pressure of less than 50 mbar,
preferably less than 25 mbar, more preferably less than 20 mbar,
wherein in step (d2) the temperature is increased in comparison to
step (d1) or in step (d2) the pressure is lowered in comparison to
step (d1), or in in step (d2) both the temperature is increased and
the pressure is lowered in comparison to step (d1).
DETAILED DESCRIPTION
[0026] In step (d1) the initial phenol concentration of the
crystals is at least 50 wt.-% and then is reduced to a value of
below 10 wt.-%.
[0027] Preferably in step (d1) the temperature is higher than or
equal to 135.degree. C. and less than or equal to 160.degree. C.,
more preferably higher than or equal to 135.degree. C. and less
than or equal to 145.degree. C.
[0028] Preferably in step (d2) the temperature is at least
20.degree. C. higher than in step (d1).
[0029] Further preferably in step (d2) the pressure is at least 10
mbar lower than in step (d1).
[0030] Further preferably in step (b) the BP-TMC-phenol-adduct is
obtained as crystals comprising BP-TMC and phenol.
[0031] After the completion of step (d) the BP-TMC is obtained as
crystals.
[0032] Further preferably at least one of steps (d1) or (d2) is
conducted in a rotary dryer.
[0033] Further preferably the phenol is removed from the
BP-TMC-phenol-adduct crystals in absence of any organic solvent
except phenol.
[0034] Further preferably neither the BP-TMC-phenol-adduct nor the
BP-TMC are molten during steps (d1) or (d2), i.e. that both the
BP-TMC-phenol-adduct and the BP-TMC are crystals during steps (d1)
or (d2).
[0035] Further preferably the BP-TMC obtained in step (d2) has a
phenol content of less than 1000 ppm, preferably less 300 ppm, more
preferably less than 200 ppm, most preferably less than 150
ppm.
[0036] Further preferably steps (d1) and (d2) are performed
continuously.
[0037] Further preferably in step (d1) the phenol concentration of
the crystals is reduced to below 5 wt.-%.
[0038] Further preferably in step (a) the gaseous acidic catalyst
comprises hydrogen chloride and hydrogen sulfide. Preferably the
gaseous acidic catalyst is a mixture of hydrogen chloride and
hydrogen sulfide.
[0039] Further preferably in step (b) the BP-TMC-phenol-adduct is
separated by [0040] (b1) removing the catalyst and the water by
distillation, [0041] (b2) crystallizing the BP-TMC-phenol-adduct
from the distillation residue, and [0042] (b3) separating the
BP-TMC-phenol-adduct by filtration.
[0043] Further preferably the process further comprising the step
of [0044] (c) recrystallizing the BP-TMC-phenol-adduct crystals
obtained in step (b) from liquid phenol.
[0045] Further preferably an amount of 20 to 60 wt.-%, preferably
30 to 50 wt.-% of the 3,3,5-trimethylcyclohexylidene bisphenol
obtained in step (d2) is conducted back to step (d1).
[0046] The process according to the invention provides a BP-TMC
with a purity of at least 99 wt.-% having a phenol content of less
than 1000 ppm, preferably of less than 300 ppm, most preferably of
less than 200 ppm. Due to the fact that neither the
BP-TMC-phenol-adduct nor the BP-TMC are molten neither morphology
changes in the crystals occur nor degradation of BP-TMC. The
crystals obtained by the process according to the invention exhibit
a good crystal structure, too. So the BP-TMC can be used for the
preparation of polycarbonates without further preprocessing.
* * * * *